Manufacturers and those who utilize information handling systems have become extremely interested in the use of optical fibers as a means for transmitting information. Advantages of optical fibers over other kinds of transmission media are well known. For example, such systems are resistant to electromagnetic interference which occasionally plagues systems using electrical cables. Additionally, optical systems are considered more secure than electrical systems since it is substantially more difficult for unauthorized personnel to tap or access an optical fiber without being detected.
As is also known, optical fibers transmit information using single or multiple strands of fibers each having an inner circular glass core coated with a circumferential cladding having a different index of refraction. Light is transmitted along the core and reflected internally of the cladding. Transmission lines as used in information handling systems known today are formed of either a single fiber or a plurality (bundle) of such fibers encased within a protective sheath. As also known, such fibers are coupled to various fiber optic connector assemblies and utilized within computers in selected manners.
One such example is shown in U.S. Pat. No. 4,678,264 (Bowen et al). Such connections are typically of the single or duplex variety, the latter involving a pair of optical fiber cables terminating within a single connector member which is designed for being inserted within a respective housing located on a designated component (e.g., a printed circuit card) which forms part of the computer. In the case of a single cable, this is also located within a connector member designed for insertion within a respective housing. Such housings may be positioned on or relative to the circuit card and are particularly designed to accommodate the fiber optic connector therein such that appropriate optical connections can be accomplished between the optical fibers and associated elements (e.g., transmitters and receivers) employed in the system when the connector is so positioned. In those situations wherein transmitter and receiver elements are used in a paired, adjacent orientation and coupled to the circuitry of the circuit card or like member, a duplex form of connector is preferably used. Further, it is also known in such computer systems to utilize a plurality of such cards and electrically connect these to a common backplane circuit board member or the like, said board member also forming part of the overall system. The various cards, board, connectors, wiring and several other elements are located within what is often referred to as a cage assembly, which assembly may form one of several such assemblies within the overall system. Still further, such computer systems may in turn include their own power supply or the like, which in turn may be connected to a local power source.
Many in the computer industry have expressed the desire to make electrical connections between the circuit card and board components within the system without shutting down the system. This is desired to permit card replacement, repair and upgrading without interruption to the services being provided by the computer. This feature is particularly desired by those among the telephony and high end computer users and designers.
Early attempts at such "power on" connections were achieved by simply plugging in the card while the computer was in operation. The unfortunate results of such an operation included the formation of arcs where such connections were made or broken. Additionally, errors in software operation were detected during such connections, subsequently attributed to the aforementioned arcing. More drastically, on some occasions the connection did fail, said failure also deemed the result of the arcing. Arcing of this type particularly occurs when a significant potential difference exists between the board and card members. Excessively high current flows as the result of the system's power supply charging the capacitance of the card as rapidly as possible. By way of example, the portion of the connector within the computer into which the card is to be inserted may be at a voltage of about 25 volts while the card is at a voltage of zero. Arc generation resulting from such a differential may in turn create "noise" in the form of electromagnetic waves which propagate within the computer, affecting other components (occasionally in an adverse manner). For example, such components may pick up this noise as a standard internal signal and react accordingly. Significant errors can thus be created in both system and software operation as a result of such arcing.
To overcome the above highly undesirable results, while still providing desired optical connections between selected optical fiber elements and respective components which form part of a circuit card member, the present invention provides a fiber optic connector assembly capable of being positioned on such a circuit card and adapted for not only receiving a fiber optic connector but also uniquely providing a means whereby electrical connections can be made to the circuit card in the same vicinity of the card as the connector assembly's housing such that charging of the card and its electrical components (e.g., to the potential of the board to which this and other cards may be electrically coupled) can occur, thereby preventing arcing or the like from occurring during such coupling or uncoupling. As will be defined further herein, such charging of the card occurs with the card separated from the mother board member such that the card's electrical potential can be raised to that of the board whereupon card coupling can occur. The charging unit can then be facilely removed from the card and the desired fiber optic connector positioned within the assembly.
It is believed that such a connector assembly would constitute a significant advancement in the art.